Temperature controlled plasma processing chamber component with zone dependent thermal efficiences

ABSTRACT

Components and systems for controlling a process or chamber component temperature as a plasma process is executed by plasma processing apparatus. A first heat transfer fluid channel is disposed in a component subjacent to a working surface disposed within a plasma processing chamber such that a first length of the first channel subjacent to a first temperature zone of the working surface comprises a different heat transfer coefficient, h, or heat transfer area, A, than a second length of the first channel subjacent to a second temperature zone of the working surface. In embodiments, different heat transfer coefficients or heat transfer areas are provided as a function of temperature zone to make more independent the temperature control of the first and second temperature zones.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of application Ser. No. 13/111,384filed May 19, 2011 which claims the benefit of U.S. ProvisionalApplication No. 61/354,158 filed Jun. 11, 2010, entitled “TEMPERATURECONTROLLED PLASMA PROCESSING CHAMBER COMPONENT WITH ZONE DEPENDENTTHERMAL EFFICIENCIES,” the entire contents of which are herebyincorporated by reference in its entirety for all purposes.

BACKGROUND

1) Field

Embodiments of the present invention generally relate to plasmaprocessing equipment, and more particularly to methods of controllingtemperatures during processing of a workpiece within a plasma processingchamber.

2) Description of Related Art

In a plasma processing chamber, such as a plasma etch or plasmadeposition chamber, the temperature of a chamber component is often animportant parameter to control during a process. For example, atemperature of a substrate holder, commonly called a chuck or pedestal,may be controlled to heat/cool a workpiece to various controlledtemperatures during the process recipe (e.g., to control an etch rate).Similarly, a temperature of a showerhead/upper electrode or othercomponent may also be controlled during the process recipe to influencethe processing (e.g., etch rate uniformity).

Often, various constraints on design of a plasma processing chambernecessitate introducing a heat transfer media to a temperaturecontrolled component in a manner which results in heat transfer withinportions of the component that are not desired. For example, where aprocess gas distribution showerhead or workpiece chuck has a pluralityof zones which can be independently controlled to separate setpointtemperatures or to better manage disparate heat loads between the zones,a heat transfer media utilized for control of a first temperature zone(i.e., a target zone) may also pass proximate to a second temperaturezone (i.e., a collateral zone) en route to, or from, the targettemperature zone. As such, driving the plurality of temperature zonesindependently can introduce significant cross-talk between the zones aswell as significant temperature non-uniformity within the collateralzone.

SUMMARY

Components and systems for controlling a process or chamber componenttemperature as a plasma process is executed by plasma processingapparatus are described herein. In certain embodiments, plasmaprocessing chamber component having a working surface is disposed withina plasma processing chamber. A first heat transfer fluid channel isdisposed in the component subjacent to the working surface such that afirst length of the first channel subjacent to a first zone of theworking surface comprises a different heat transfer coefficient, h, orheat transfer area, A, than a second length of the first channelsubjacent to a second zone of the working surface. For example, wherethe second length is downstream of the first length, the first lengthhas a lower heat transfer coefficient h than does the second length sothat the first heat transfer fluid has a lesser impact (e.g., reducedheat transfer rate {dot over (Q)}) on the first zone temperature thanthe first heat transfer fluid does on the second zone. In embodiments,different heat transfer coefficients or heat transfer areas are providedas a function of temperature zone to make more independent thetemperature control of the first and second temperature zones.

In a further embodiment, where the component includes a second heattransfer fluid channel disposed subjacent to the first zone of theworking surface, the heat transfer coefficient or heat transfer areaalong a length of the second channel is made greater than that of thefirst length of the first channel so that a second heat transfer fluidpassing through the second channel may have a greater impact on thefirst zone temperature than does the first heat transfer fluid passingthrough the first length of the first channel. In one exemplaryembodiment, where the component is a substrate chuck or process gasshowerhead, the working surface is circular and the first zone comprisesan annular portion of the circular working surface which surrounds thesecond zone.

In certain embodiments, the lengths of heat transfer fluid channels areengineered to modulate one of a heat transfer coefficient or heattransfer area. In one particular embodiment, the heat transfercoefficient along the first length is made lower than the second lengththrough incorporation of a sleeve of a thermally resistive materialabout the first length of channel to increase the thermal resistancerelative to the second length. In another embodiment, a first length ofthe first channel is disposed at a greater distance subjacent to theworking surface along the first length than along the second lengthand/or at a greater distance than is a length of the second heattransfer fluid channel. A thermal break, such as an evacuate space ornon-metallic material may in addition, or in the alternative, bedisposed between the first channel and the working surface along atleast a portion of the first length to increase the thermal resistancerelative to the second length.

In embodiments, the heat transfer area along the first length is madelower than the second length, for example through incorporation of finsalong the second length that are absent in the first length.

Embodiments include a plasma processing chamber, such as a plasma etchor plasma deposition system, having a temperature-controlled componentto be coupled to a heat sink/heat source. The temperature-controlledcomponent may be coupled to a first heat sink/source by a first heattransfer fluid loop, the first fluid loop passing through first andsecond lengths of a channel embedded in first and second zones of thetemperature-controlled component, respectively. Thetemperature-controlled component may be further coupled to a second heatsink/source by a second heat transfer fluid loop, the second fluid looppassing through channel lengths embedded only in the first zone. Thefirst length of the first channel may have a heat transfer coefficientor heat transfer area different than that of the second length and/orsecond channel.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are particularly pointed out and distinctlyclaimed in the concluding portion of the specification. Embodiments ofthe invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings in which:

FIG. 1A is a layout view of a temperature controlled plasma processingchamber component comprising a working surface having a plurality oftemperature zones, in accordance with an embodiment of the presentinvention;

FIGS. 1B and 1C are plan views of the temperature controlled plasmaprocessing chamber component illustrated in FIG. 1A, illustratingworking surface temperature variations in a first zone, in accordancewith an embodiments of the present invention

FIG. 2A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 2B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 3A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 3B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 4A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 4B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 5A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 5B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 6A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 6B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component depicted inFIG. 1, in accordance with an embodiment of the present invention;

FIG. 7 illustrates a schematic of a plasma etch system including atemperature controlled process gas showerhead, in accordance with anembodiment of the present invention; and

FIG. 8 illustrates a schematic of a plasma etch system including atemperature controlled substrate supporting chuck, in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of embodiments of theinvention. However, it will be understood by those skilled in the artthat other embodiments may be practiced without these specific details.In other instances, well-known methods, procedures, components andcircuits have not been described in detail so as not to obscure thepresent invention.

The terms “coupled” and “connected,” along with their derivatives, maybe used herein to describe structural relationships between components.It should be understood that these terms are not intended as synonymsfor each other. Rather, in particular embodiments, “connected” may beused to indicate that two or more elements are in direct physical orelectrical contact with each other. “Coupled” my be used to indicatedthat two or more elements are in either direct or indirect (with otherintervening elements between them) physical or electrical contact witheach other, and/or that the two or more elements co-operate or interactwith each other (e.g., as in a cause and effect relationship).

Described herein are plasma chamber components including a first heattransfer fluid channel in which a portion of the channel disposedoutside of a target temperature zone of the component is designed tohave a lower heat transfer coefficient h or heat transfer area A than aportion of the first channel disposed within the target zone of thecomponent. By reducing the heat transfer coefficient h and/or heattransfer area A, the effect of the heat transfer fluid flowing throughthe first channel portion outside of the target zone on the temperatureof a working surface of the component outside of the target zone may bereduced even if the thermodynamic driving force ΔT is largest outside ofthe target temperature zone. This is particularly advantageous forplasma chamber components that include a second temperature-controlledzone through which the first heat transfer fluid channel passes throughto access the target zone. As such, a temperature of a working surfacein the second zone is made less of a function of the first heat transferfluid channel and uniformity of the surface temperature within thesecond zone may be improved.

In an embodiment, a temperature-controlled plasma processing chambercomponent includes a working surface disposed within a plasma processingchamber, such as the plasma etch systems depicted further in FIGS. 7 and8. FIG. 1A is a layout view of exemplary temperature-controlled plasmaprocessing chamber component 100, in accordance with an embodiment ofthe present invention. In a first exemplary embodiment, as furtherillustrated in FIG. 7, the component 100 is a process gas distributionshowerhead through which a process gas may be provided to a plasmaprocessing chamber. In a second exemplary embodiment, as furtherillustrated in FIG. 8, the component 100 is a workpiece supporting chuckor pedestal upon which a workpiece is disposed during a plasmaprocessing operation. In still another embodiment, atemperature-controlled plasma processing chamber component adapted toprovide the features/functionality described herein for the exemplaryembodiments includes a chamber wall liner.

For the first and second exemplary embodiments, the component 100includes a circular working surface 126 which may be exposed to theplasma (e.g. for a showerhead embodiment) or may be supporting aworkpiece (e.g., for a chuck embodiment). In FIG. 1A, the workingsurface 126 may be considered transparent for the purpose of visualizingheat transfer fluid channels subjacent to (below) the working surface126. The working surface 126 however is typically to be of asemiconductor (e.g., silicon) an anodized surface (e.g., Al₂O₃), aceramic (e.g., ytterium oxides), or any other material conventional to aplasma processing apparatus. As illustrated, the temperature zone 105has an annular shape while the temperature zone 110 is circular in shapeand encircled or circumscribed by the temperature zone 105 to form“inner” and “outer” temperature zones of the component 100. The annulararrangement of the zones 105 and 110 is a function of the cylindricalsymmetry of a plasma processing apparatus configured to processdisk-shaped wafer substrates conventional in thesemiconductor/microelectronic/electro-optical manufacturing art and itshould be appreciated that in other embodiments two temperature zonesmay merely be adjacent (e.g., for in-line plasma processing apparatusesconventional in photovoltaic manufacture, etc.).

In an embodiment, a temperature-controlled plasma processing chambercomponent includes at least one heat transfer fluid channel subjacent toa working surface 126 and forming a portion of a heat transfer fluidloop coupled to the plasma processing apparatus. The heat transfer fluidmay be any heat transfer fluid known in the art to be suitable for thepurpose(s) of transferring heat to/from the component 100 (specificallythe working surface 126 where a heat load will be placed) for thepurpose of controlling one or more of the plurality of temperaturezones. Examples of suitable heat transfer fluids include water-basedmixtures, such as Galden® (available from Solvay S. A.) or Fluorinert™(available from 3M Company). In the exemplary embodiment depicted, afirst heat transfer fluid channel includes a plurality of fluid channellengths 112A, 113A and 114A. As depicted, heat transfer fluid 1 flowsinto the component 100, through a first channel length 112A, to a secondchannel length 113A downstream of the first channel length 112A, to athird channel length 114A downstream of the second channel length 113A,and out of the component 100. The channel lengths 112A, 113A, 114A areembedded within the component 100 to be subjacent to the working surface126.

In an embodiment, a temperature-controlled plasma processing chambercomponent includes a plurality of temperature zones. Generally, thetemperature zones are adjacent/circumjacent regions of a working surfaceto be disposed within a plasma processing chamber and the temperaturezones are controllable to a setpoint temperature independent of oneanother. Independence of the temperature zones prevents different heattransfer fluid flows within the different zones (as provided to controla target zone's temperature) from affecting the temperature another zone(e.g., collateral zone). For example, where some form offeedback/feedforward control is utilized and according to the controlalgorithm a first zone required a large heat transfer fluid flow and asecond required no heat transfer fluid flow then the large flow throughthe heat transfer fluid channel accessing the first zone via the secondzone should not alter the temperature of the second zone.

The temperature zone for which a particular heat transfer fluid controls(i.e., target zone) is a function of the heat transfer rate {dot over(Q)} provided by the heat transfer fluid passing through a particularheat transfer fluid channel within that zone, with fluid channels thatprovide a higher heat transfer rate {dot over (Q)} applying a largercontrol effort at a particular location on the working surface 126.Generally, the larger the disparity in heat transfer rate {dot over (Q)}a heat transfer fluid has between different temperature zones (e.g.,{dot over (Q)}_(zone 1) to {dot over (Q)}_(zone 2)), the lower thecross-talk, and greater the temperature independence of adjacent zones.Consider a heat transfer matrix between a first temperature zone and asecond temperature zone:

{dot over (Q)}₁₁ {dot over (Q)}₁₂

{dot over (Q)}₂₁ {dot over (Q)}₂₂′

where {dot over (Q)}₁₁ represents a first heat transfer fluid affect onzone 1, {dot over (Q)}₁₂ represents the first heat transfer fluid affecton the second zone, {dot over (Q)}₂₁ represents the second heat transferfluid affect on the first zone and {dot over (Q)}₂₂ represents thesecond heat transfer fluid affect on the second zone. The crosstalkterms {dot over (Q)}₁₂ and {dot over (Q)}₂₁ are to be minimized whilemaximizing {dot over (Q)}₁₁ and {dot over (Q)}₂₂ for independenttemperature control of each zone (e.g., via a feedforward and/orfeedback mechanism).

In one embodiment, a plurality of temperature zones is provided via aplurality of heat transfer elements within the temperature-controlledcomponent. A heat transfer element may be any known in the art, such asa heat transfer fluid channel, a thermoelectric (TE) element, aresistive heating element, etc. In the exemplary embodiment including afirst heat transfer fluid channel, a plurality of temperature zones maybe provided by adding a second, third, etc. heating element incombination with the first heat transfer fluid channel. For example, afirst heat transfer fluid channel may be combined with a TE element or aresistive heating element. For the exemplary embodiment illustrated inFIG. 1A, however, a first heat transfer fluid channel is combined with asecond heat transfer fluid channel 107A to provide the plurality oftemperature zones. More specifically, the second heat transfer fluidchannel 107A is subjacent to the temperature zone 105. As illustrated,all lengths 132A, 133A and 134A of the second heat transfer fluidchannel 107A are within the temperature zone 105 so that the fluid 2feeds into the component 100 and out of the component 100 withoutpassing through another temperature zone.

In an embodiment, the temperature-controlled plasma processing chambercomponent 100 includes at least one heat transfer fluid channel havingchannel lengths within more than one temperature zone. In the exemplaryembodiments represented by FIG. 1A, a first heat transfer fluid channelhas channel lengths in both the temperature zone 105 (e.g., lengths 112Aand 114A) and temperature zone 110 (e.g., length 113A). Thus, at least afeed and/or a return of the fluid 1 passes through the temperature zone105. Depending on the path configuration of a heat transfer fluidchannel, a channel length in a first zone (e.g., temperature zone 105)may be approximately equal in length to a channel length in a second,adjacent zone (e.g., temperature zone 110). Whether the secondtemperature zone (e.g., temperature zone 110) is controlled via a secondheat transfer fluid channel or otherwise (e.g., TE element), having atleast one heat transfer fluid channel with channel lengths within morethan one temperature zone may induce undesirable cross-talk betweenadjacent temperature zones (e.g., large {dot over (Q)}₁₂ and {dot over(Q)}₂₁ terms) and induce significant variation in the temperature of acomponent's working surface, as illustrated in FIG. 1B. Nevertheless,other hardware limitations (e.g., process gas distribution assemblies,lift pin assemblies, etc.) may motivate such a fluid channel layout.

As further illustrated in FIG. 1A, additional heat transfer fluidchannels may be incorporated into the component 100 to improve surfacetemperature control (e.g., uniformity of heat transfer rate). Forexample, the temperature zone 110 further includes a third heat transferfluid channel including lengths 112B, 113B, and 114B disposed in thecomponent 100 in a manner symmetrical to the lengths 112A, 113A, and114B about a central axis 101 of the component (i.e., azimuthally (θ)symmetrical) to provide a second, parallel source of fluid 1 into thetemperature zone 110. Analogously, the temperature zone 105 furtherincludes a fourth heat transfer fluid channel 107B disposed in thecomponent 100 in a manner symmetrical to the second heat transfer fluidchannel 107A about a center of the component. For clarity of discussion,lengths 112A, 113A, 114A, 112B, 113B, and 114B are referenced in thealternative, as is channel 107A and channel 107B, with the understandingthat characteristics of references numbers with an “A” suffix are alsoapplicable to the same reference number with a “B” suffix.

In embodiments, lengths of a heat transfer fluid channel within a targettemperature zone have a different heat transfer coefficient h ordifferent heat transfer area A than do lengths of the heat transferfluid channel outside of the target temperature zone (i.e., within acollateral temperature zone). In an embodiment, a first length of thefirst channel subjacent to a first zone of the working surface comprisesa different heat transfer coefficient h than a second length of thefirst channel subjacent to a second zone of the working surface. For theexemplary embodiments represented by FIG. 1A, the heat transfercoefficient h along the channel length 112A is different than the heattransfer coefficient h along the channel length 113A. In a particularembodiment, the heat transfer coefficient h along the channel length112A is lower than the heat transfer coefficient h along the channellength 113A.

In another embodiment, a first length of the first channel subjacent toa first zone of the working surface comprises a different heat transferarea A than a second length of the first channel subjacent to a secondzone of the working surface. For the exemplary embodiments representedby FIG. 1A, the heat transfer area A along the channel length 112A isdifferent than the heat transfer area A along the channel length 113A.In a particular embodiment, the heat transfer area A along the channellength 112A is lower than the heat transfer area A along the channellength 113A.

In further embodiments, the amount by which the heat transfercoefficient h and/or the heat transfer area A is lower along the firstchannel length than the second channel length is larger than anyreduction in ΔT between the two channel lengths such that a relativelylower heat transfer rate in the first channel length is achieved evenfor an upstream length of the channel where ΔT may be expected to begreater than for a downstream length. For the exemplary embodimentsrepresented by FIG. 1A, the product hA along the channel length 112A islower than the product hA along the channel length 113A.

In a further embodiment, a third length of a first heat transfer fluidchannel downstream of the second length and also subjacent to the firstzone has a heat transfer coefficient h or heat transfer area A that islower than along the second length. For example, referring back to FIG.1B, the length 114A has a lower heat transfer coefficient h and/or heattransfer area A than along the length 113A (length within target zone110). As such, where either or both the heat transfer coefficient hand/or the heat transfer area A is reduced sufficiently for a firstchannel (e.g., 112A) disposed in a non-targeted zone (e.g., 105),cross-talk with a second channel (e.g., 107A) disposed subjacent to thefirst zone may be reduced and where the second channel is to conduct asecond heat transfer fluid at a second temperature, the temperature ofthe working surface (e.g., 126) within the first zone may be made moreuniformly controlled to a setpoint temperature by the second heattransfer fluid targeted at the first zone (e.g., as depicted in FIG.1C).

FIG. 2A illustrates a cross-sectional view along the A-A′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1, in accordance with an embodiment of the present invention.The component 100 is a multi-leveled assembly including at least a firstlayer 220 and a second layer 225. Each layer 220 and 225 may, forexample, be of a material conventional to a single level component. Incertain embodiments, the second layer 225 is of a material with highthermal conductivity to reduce thermal spreading resistance across theworking surface 126. In other embodiments however, the second layer 225is of a material with low thermal conductivity to localize heat transferto regions of the working surface 126 most proximate to a heat transferfluid channel.

The component 100 further includes a plurality of heat transfer fluidchannel levels with the channel length 114A formed within the layer 220and the channel length 113A formed within the layer 225. The first andsecond heat transfer fluid levels are interconnected via connectors 228formed in a capping layer 227. In a particular embodiment, the component100 first layer 220 is machined to form a first pattern of first heattransfer fluid channel lengths (e.g., length 114A). The capping layer227 is then machined to have connectors 228 corresponding to locationsof the first heat transfer fluid channels and then affixed (e.g.,brazed, soldered, thermally bonded, etc.) to the first level 200,thereby enclosing the first heat transfer fluid channels. The secondlayer 225 is similarly machined to form a second pattern of second heattransfer fluid channel lengths (e.g., length 113A) and the second layer225 is similarly affixed to the capping layer 227. The thermalresistance R₁ in the collateral zone (e.g., zone 105) may be madesubstantially larger than the thermal resistance R₂ in the target zone(e.g., zone 110), for example because of the lower heat transfercoefficient attributable to the larger distance and/or the additionalcapping layer 227 (which may be selected to have a relatively lowerthermal conductivity) between the working surface 126 and the channellength 114A relative to the channel length 113A.

As further illustrated in FIG. 2A, the heat transfer coefficient hand/or heat transfer area A along the length 114A of the first channelis lower than along an equal length of the second channel 107A. Wherethe second channel 107A is targeted to provide temperature control ofthe working surface 126 in the zone 105, the second channel 107A isdisposed within the layer 225 to be more proximate to the workingsurface 126 than is the length 114. For embodiments as depicted in FIG.1A, where the entire second channel 107A is disposed with the zone 105,all lengths 132A, 133A and 134A may be disposed within the layer 225.However sections 132A and 134A may be in layer 220 as it may affect thesymmetry about the central axis 101 along the azimuth angle θ.

FIG. 2B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1, in accordance with an embodiment of the present invention. Asfurther illustrated, both the first and third lengths 112B and 114B of aheat transfer fluid channel within the non-targeted temperature zone 105are associated with larger thermal resistances R1, for example becauseof the lower heat transfer coefficient h attributable to the largerdistance and/or the additional capping layer 227 (which may be selectedto have a relatively lower thermal conductivity) between the workingsurface 126 and the first and third heat transfer fluid channel lengths112B and 114B.

In an embodiment, a temperature-controlled component includes a thermalbreak disposed between a working surface and a length of a heat transferfluid channel in a non-targeted temperature zone to increase the thermalresistance relative to a second length of the heat transfer fluidchannel located within a target temperature zone. A thermal breakcomprises a region of a relatively lower thermal conductivity than thebulk of component 100. FIG. 3A illustrates a cross-sectional view alongthe A-A′ line of the temperature controlled plasma processing chambercomponent 100 depicted in FIG. 1, in accordance with an embodiment ofthe present invention. As shown, a thermal break 330 is disposed betweenat least a portion of the channel length 114A and the working surface126 to increase the thermal resistance between the working surface 126and a point within the channel length 114A to R1 relative to the thermalresistance R2 between the working surface 126 and a point within thechannel length 113A. In one embodiment, the thermal break 330 comprisesan evacuated or rarefied space. The thermal break 330 may be formed as achannel in the layer 225 in a manner similar to the heat transfer fluidchannel 113A, however the thermal break 330 is sealed by the cappinglayer 227 such that no connector 228 is provided subjacent to thethermal break 330 and a void which is not to conduct a heat transferfluid is formed within the layer 225. In other embodiments, the channelformed in layer 225 is filled with a material having a lower thermalconductivity than the bulk of the layer 225, for example a non-metallicmaterial, such as ceramics, plastics, polyimides, Teflon®, Kapton®, etc.In an alternative embodiment, the capping layer 227 may further servethe function of a thermal break either by incorporating a rarefied spacebetween opposing surfaces of the capping layer 227 (each mating with oneof the layers 220 and 225) or by comprising a material of relativelylower thermal conductivity.

FIG. 3B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1, in accordance with an embodiment of the present invention. Asillustrated, both the first and third lengths 112B and 114B of a heattransfer fluid channel within the non-targeted temperature zone 105 areassociated with larger thermal resistances R1, for example because ofthe lower heat transfer coefficient h attributable to the thermal breakhaving a relatively lower thermal conductivity than the bulk of layer225 between the working surface 126 and the first and third heattransfer fluid channel lengths 112B and 114B.

In one embodiment, a heat transfer fluid channel comprises a number offins along a length within a target temperature zone that are absentfrom a length of the channel outside of the target zone such that theheat transfer area A is made larger in for the channel length within thetarget zone. FIG. 4A illustrates a cross-sectional view along the A-A′line of the temperature controlled plasma processing chamber component100 depicted in FIG. 1, in accordance with an embodiment of the presentinvention. As depicted, within the zone 110, the channel length 113Aincludes a plurality of topological features 440 (e.g., fins),increasing the heat transfer area/length (A/L) for a channel length 113Arelative the channel length 114B. As such the cumulative thermalresistance R2/length along the channel length 113A may be made less thanthe thermal resistance R1/length along the channel length 114B. Incertain further embodiments, topological features 440 may also beprovided in a second heat transfer fluid channel 107A.

FIG. 4B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1, in accordance with an embodiment of the present invention. Asillustrated, both the first and third lengths 112B and 114B of a heattransfer fluid channel within the non-targeted temperature zone 105 areassociated with larger thermal resistances R1, for example because of alower heat transfer area/length A/L attributable to the absences oftopological features 440 in heat transfer fluid channel lengths 112B and114B. As further illustrated in FIGS. 4A and 4B, modulation of the heattransfer area between lengths of a heat transfer fluid channel may allowfor a simplified assembly including only the layer 225 and a singlelevel of channels. Of course, because most any embodiment describedherein may be combined with any other, a multi-level channelconfiguration (e.g., FIGS. 2A-3B) may also be implemented in combinationwith the modulation in heat transfer area to increase the disparity inheat transfer rate between various lengths of the channel.

In an embodiment a thermally resistive material forms a sleeve around aheat transfer fluid channel length to increase the thermal resistancerelative to a second length of the channel lacking such a channelsleeve. FIG. 5A illustrates a cross-sectional view along the A-A′ lineof the temperature controlled plasma processing chamber component 100depicted in FIG. 1, in accordance with an embodiment of the presentinvention. As illustrated, a thermally resistive channel sleeve 550 ispresent along at least a portion of the channel length 114B. Thethermally resistive material may, for example be any of those describedfor thermal break embodiments with the primary distinction betweenthermal break embodiments and thermally resistive sleeve embodimentsbeing that the thermally resistive material is disposed adjacent tosidewalls of the heat transfer fluid channel in addition to beingpresent between the heat transfer fluid channel and the working surface.As further illustrated in FIG. 5A, the thermally resistive sleeve 550may further be disposed on a side of the channel opposite the workingsurface to completely surround the channel with the thermally resistivematerial. In other embodiments however, the thermally resistive sleeve550 is only present on 3 sides of the channel (e.g., as depicted in FIG.5B illustrating a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1).

Thermally resistive channel sleeve embodiments may further allow for asingle channel level construction of the component (e.g., embeddedwithin layer 225). Many techniques known in the art may be utilized toform the thermally resistive sleeve 550, depending on the thermallyresistive material chosen. For example, a coating process may beselectively applied and/or selectively removed to/from lengths ofchannels machined into the layer 225. In other embodiments, largeregions of layer 225 replaced with the thermally resistive material isthen machined to form channels within the thermally resistive material.As further illustrated in FIG. 5B, both the first and third lengths 112Band 114B of a heat transfer fluid channel within the non-targetedtemperature zone 105 are associated with larger thermal resistances R1,for example because of a lower heat transfer coefficient attributable tothe resistive sleeves 550 along the heat transfer fluid channel lengths112B and 114B.

In another embodiment, a heat transfer fluid channel length has a firstcross-sectional area larger than a second cross-sectional area of asecond length to modulate an extent of convection occurring within theheat transfer fluid as it passes through the fluid channel duringoperation. FIG. 6A illustrates a cross-sectional view along the A-A′line of the temperature controlled plasma processing chamber component100 depicted in FIG. 1, in accordance with an embodiment of the presentinvention. In the exemplary embodiment depicted, a cross-sectional areaof along the channel length 114B is sufficiently large to ensure laminarflow of the heat transfer fluid along at least a portion of the channellength 114B while the cross-sectional area along the channel length 113Bis sufficiently small to induce turbulent flow of the heat transferfluid along at least a portion of the channel length 113B. In otherembodiments where the heat transfer fluid flow velocity within thechannel length 114B and 113B are both in the turbulent or laminarregime, different fluid velocities within the lengths 114B and 113Bnevertheless result in different heat transfer coefficients h betweenthe two lengths with higher velocity providing higher heat transfer. Itshould also be appreciated that the cross sectional area of the heattransfer fluid channel may be so modulated in combination with the otherembodiments described herein (e.g., in FIGS. 2A-5B) modulation of theheat transfer fluid flow velocity may be

For the depicted embodiment the channel cross-sectional area ismodulated by machining the capping layer 227 to have relief where alarger cross-sectional area is to be (e.g., in non-targeted temperaturezones that overly the channel length 114B) and to have a full cappinglayer thickness where a smaller cross-sectional area is to be (e.g., intargeted temperatures zones that overly the channel length 113B). FIG.6B illustrates a cross-sectional view along the B-B′ line of thetemperature controlled plasma processing chamber component 100 depictedin FIG. 1, in accordance with an embodiment of the present invention. Asillustrated, both the first and third lengths 112B and 114B of a heattransfer fluid channel within the non-targeted temperature zone 105 areassociated with larger thermal resistances R1, for example because of alower heat transfer coefficient attributable to the reduced convectionin laminar/lower velocity flow regimes within in heat transfer fluidchannel lengths 112B and 114B. As further illustrated in FIGS. 6A and6B, modulation of the heat transfer area between lengths of a heattransfer fluid channel may allow for a simplified assembly includingonly the layer 225 and a single level of channels. It should also benoted that larger cross-sectional areas may be provided by increasing alateral width of the channel.

FIGS. 7 and 8 illustrate a plasma etch system including a temperaturecontrolled component, in accordance with an embodiment of the presentinvention. The plasma etch system 700 may be any type of highperformance etch chamber known in the art, such as, but not limited to,Enabler™, MxP®, MxP+™, Super-E™, DPS II AdvantEdge™ G3, or E-MAX®chambers manufactured by Applied Materials of CA, USA. Othercommercially available plasma etch chambers may include similartemperature-controlled components. While the exemplary embodiments aredescribed in the context of the plasma etch system 700, it should befurther noted that the temperature control system architecture describedherein is also adaptable to other plasma processing systems (e.g.,plasma deposition systems, etc.) which present a heat load on atemperature-controlled component.

The plasma etch system 700 includes a grounded chamber 705. A substrate710 is loaded through an opening 715 and clamped to a chuck 721. Thesubstrate 710 may be any workpiece conventionally employed in the plasmaprocessing art and the present invention is not limited in this respect.The plasma etch system 700 includes a temperature-controlled process gasshowerhead 735. In the exemplary embodiment depicted, the process gasshowerhead 735 includes a plurality of zones 110 (center) and 105(edge), each zone independently controllable to a setpoint temperature.Other embodiments have either more than two zones. For certainembodiments with more than one zone, there are n heater zones and mcoolant zones where n need not be equal to m. For example, in theembodiment depicted, a single cooling loop (m=1) passes through twotemperature zones (n=2). Process gases, are supplied from gas source 745through a mass flow controller 749, through the showerhead 735 and intothe interior of the chamber 705. Chamber 705 is evacuated via an exhaustvalve 751 connected to a high capacity vacuum pump stack 755.

When plasma power is applied to the chamber 705, a plasma is formed in aprocessing region over substrate 710. A plasma bias power 725 is coupledto the chuck 721 (e.g., cathode) to energize the plasma. The plasma biaspower 725 typically has a low frequency between about 2 MHz to 60 MHz,and in a particular embodiment, is in the 13.56 MHz band. In theexemplary embodiment, the plasma etch system 700 includes a secondplasma bias power 726 operating at about the 2 MHz band which isconnected to the same RF match 727 as plasma bias power 725. A plasmasource power 730 is coupled through a match 731 to a plasma generatingelement to provide source power to inductively or capacitively energizethe plasma. The plasma source power 730 typically has a higher frequencythan the plasma bias power 725, such as between 100 and 180 MHz, and ina particular embodiment, is in the 162 MHz band.

The temperature controller 775 may be either software or hardware or acombination of both software and hardware. The temperature controller775 is to output control signals affecting the rate of heat transferbetween the showerhead 735 and a heat source and/or heat sink externalto the plasma chamber 705 based on at least temperature sensors 766 and767. In the exemplary embodiment, the temperature controller 775 iscoupled, either directly or indirectly, to the heat exchanger/chillers777 and 782 (or heat exchanger/chillers 777 and a TE element, resistiveheater, etc.).

The heat exchanger/chiller 777 is to provide a cooling power to theshowerhead 735 via a heat transfer fluid loop 778 thermally coupling theshowerhead 735 with the heat exchanger/chiller 777. In the exemplaryembodiment, the heat transfer fluid loop 778 passes a liquid (e.g., 50%ethylene glycol in DI water at a setpoint temperature of −15° C.)through a coolant channel embedded in both the inner zone 110 and outerzone 105 (e.g., entering proximate to a first zone and exiting proximateto the other zone) of the showerhead 735 and may therefore incorporateany of the embodiments described herein to differentiate the heattransfer of the channel between the separate zones. The temperaturecontroller 775 is coupled to a coolant liquid pulse width modulation(PWM) driver 780. The coolant liquid PWM driver 780 may be of any typecommonly available and configurable to operate the valve(s) 720 forembodiments where those valves are digital (i.e., having binary states;either fully open or fully closed) at a duty cycle dependent on controlsignals sent by the temperature controller 775. For example, the PWMsignal can be produced by a digital output port of a computer (e.g.,controller 770) and that signal can be used to drive a relay thatcontrols the valves to on/off positions.

In the embodiment depicted in FIG. 7, the system 700 includes the secondheat exchanger/chiller 782 to provide a cooling power to the showerhead735 via a heat transfer fluid loop 779. In the exemplary embodiment, theheat transfer fluid loop 779 is employed which passes a cold liquid(e.g., 50% ethylene glycol in DI water at a setpoint temperature of −15°C.) through a coolant channel embedded in only the outer zone 105 of theshowerhead 735. The temperature controller 775 is coupled to a coolantliquid pulse width modulation (PWM) driver 781 to drive a relay thatcontrols the valves 720 to on/off positions, etc.

FIG. 8 illustrates a schematic of the plasma etch system 800 including atemperature controlled substrate supporting chuck, in accordance with anembodiment of the present invention, and may be combined with theshowerhead embodiment depicted in FIG. 7 for a plasma etch systemincluding two temperature-controlled components. As further depicted inFIG. 8, the chuck 721 includes an inner zone 110 and outer zone 105,each coupled to a separate heat source/sink (heat exchanger/chillers777, 778). As illustrated the heat exchanger/chiller 777 is coupled to aheat transfer fluid channel in the chuck 721 that passes only throughthe inner zone 110 while the heat exchanger/chiller 778 is coupled to aheat transfer fluid channel in the chuck 721 that passes through boththe outer zone 105 and the inner zone 110 and may therefore incorporateany of the embodiments described herein to differentiate the heattransfer of the channel between the separate zones.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reading and understanding theabove description. Although the present invention has been describedwith reference to specific exemplary embodiments, it will be recognizedthat the invention is not limited to the embodiments described, but canbe practiced with modification and alteration within the spirit andscope of the appended claims. Accordingly, the specification anddrawings are to be regarded in an illustrative sense rather than arestrictive sense. The scope of the invention should, therefore, bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A plasma processing apparatus, comprising: a plasma power source coupled to the process chamber to energize a plasma during processing of a workpiece disposed in the process chamber; a process chamber including a temperature-controlled component coupled to a heat source or sink by a first heat transfer fluid loop, the first fluid loop passing through first and second lengths of a channel embedded in the temperature-controlled component, wherein the first length is subjacent to a first temperature zone of the component and the second length is subjacent a second temperature zone of the component, wherein the first length comprises a lower heat transfer coefficient and/or heat transfer area than the second length.
 2. The plasma processing apparatus of claim 1, wherein the temperature-controlled component is a gas distribution showerhead or a substrate supporting chuck, wherein the first temperature zone comprises an annular portion of the showerhead or chuck surrounding the second temperature zone and wherein the showerhead or chuck is further coupled to a second heat transfer fluid loop, the second fluid loop passing through a third length of a channel embedded in the temperature-controlled component subjacent to the first temperature zone of the component.
 3. The plasma processing apparatus of claim 2, wherein the first length has a lower heat transfer coefficient or heat transfer area than both the second and third lengths.
 4. The plasma processing apparatus of claim 3, wherein the heat transfer coefficient along the first length is lower than the second length.
 5. The plasma processing apparatus of claim 3, wherein the heat transfer area along the first length is lower than the second length.
 6. The plasma processing apparatus of claim 3, wherein the first length has a first cross-sectional area larger than a second cross-sectional area of the second length.
 7. A method of controlling a temperature of a working surface in a plasma processing apparatus, comprising: flowing a first heat transfer fluid through a first and second length of a first heat transfer fluid channel, wherein the first length is subjacent to an outer temperature zone of the working surface and wherein the second length is subjacent to an inner temperature zone of the working surface, the outer temperature zone forming an annulus about the inner temperature zone; flowing a second heat transfer fluid through a second heat transfer fluid channel, wherein the second heat transfer fluid channel is subjacent to the outer temperature zone of the working surface; and modulating a flow rate of the first heat transfer fluid to control the temperature of the inner temperature zone without affecting the temperature of the outer temperature zone.
 8. The method of claim 7, further comprising delivering a process gas through the component and conducting a plasma etch process of a workpiece while modulating the flow rate. 